Studies of effector pathways and regulatory mechanisms of immediate hypersensitivity and inflammation in the lung will focus on alveolar macrophage migration, immunological elaboration of chemical mediators in lung tissue and alpha-globulin modulation of neutrophil-mediated patho-inflammatory reactions in the lung. The unique biochemical prerequisites and other controls of alveolar macrophage migration will be assessed in vitro by an agarose assay and correlated with the in vivo clearance of particles from the lung. The cellular requirements for the elaboration of mediators of IgE-directed hypersensitivity reactions will be pursued utilizing mast cell-rich and various mast cell-depleted subpopulations purified from enzymatically dispersed human lung cells. The modulating effects of alpha-antitrypsin on the pulmonary inflammatory potential of neutrophil-derived proteases will be studied in terms of both the direct proteolytic activity and the liberation of peptide contractile and permeability-enhancing factors.